1. Field of the Invention
The present invention generally relates to an exchange, and more particularly to an exchange which is applicable to a call via the Internet and which has a function for switching from a call via the Internet to a call via another network.
2. Description of the Related Art
When making a call via the Internet, the charge for a call is the sum of a telephone charge to an Internet provider and a charge for the Internet provider to connect to the Internet. Therefore, communications costs can be reduced substantially. Thus, it is strongly needed to use an Internet telephone system for a long-distance call and the like.
FIG. 1 is a diagram showing an example of a conventional internet telephone system. In FIG. 1, when a personal computer of a user A originates a call to a personal computer of a user B, the personal computer of the user A designates an IP address of the personal computer of the user B, connects to the personal computer of the user B and starts a call.
As mentioned above, according to the conventional system, it is necessary to input an IP address of a called party in order to make a call via the Internet. In addition, there may be cases where speech quality is degraded according to conditions of the Internet. In such a case, conventionally, a connection via the Internet needs to be disconnected and the connection is switched to a connection via a telephone network or the like by redialing manually. In addition, a caller needs to know a plurality of numbers such as an IP address, a telephone number of a called party and the like.